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Topic: Portable heat source for testing heat detectors (Read 998 times) previous topic - next topic

joebert

Currently I carry around a hair dryer and extension cord to test the heat detectors in my buildings. I'd like to build something portable that runs on a 9-12V battery. The hottest I need is roughly 200 degrees F, more often than not I'm testing "Rate of Rise" heat detectors so a fast rise in temp is important to me.

I've looked around at common heat guns, they all seem to work on 120VAC, but they're blowing out several hundred more degrees than I need. So, I'm thinking a battery powered heat gun could be feasible for my needs. I'm not sure where to start for the heat source though. Peltier maybe?

Krodal

No, not peltier.
Peltier can be used to create a low temperature (if the warm side is cooled is a heat sink).

You only want heat, so you need a current going through a wire and a fan to blow the hot air out.
You could use a heat blower / defroster for cars.
There are also hair dryers for 12V, to be used in cars and on boats.
These devices need a lot of current though. But perhaps you can carry a backpack with a large battery.

Just an idea: If you use a heat blower or hair dryer at 12V, and make ik PWM controlled by an Arduino with a power mosfet. And if you would also measure the air temperature, you have full control over it.

PeterH


to test the heat detectors in my buildings


Is this an informal test, or are you doing some sort of certification/safety test? For the latter you need to know what standard you are testing against in order to know how to test it, and your test equipment would need to be calibrated.
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robtillaart

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wizdum



Is a gas torch an option?


You can even get little pocket-torches that run off of cigarette lighters.
"Anyone who isn't confused really doesn't understand the situation."

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joebert

Quote
These devices need a lot of current though. But perhaps you can carry a backpack with a large battery.


The boat 12VDC hair dryers/defrosters look promising. Batteries are no issue, I have a constant inflow of used 12V 7-12AH sealed lead acid batteries that aren't up to par for their intended purpose, but will work for this purpose.

Quote
Is this an informal test, or are you doing some sort of certification/safety test? For the latter you need to know what standard you are testing against in order to know how to test it, and your test equipment would need to be calibrated.


I know all about it. :)

PeterH


I know all about it. :)


Fair enough. In that case a simple hotwire element 12V hair drier seems to be all you need. You could vary the temperature either by PWM modulation on the heater element, or by varying the fan speed. Which works better would depend whether the full power output was above or below your target temperature. I suspect the common 12V driers will probably be feeble little things so you will probably be wanting to boost the temperature (by reducing the air flow) rather than lowering it (by reducing the heating power).
I only provide help via the forum - please do not contact me for private consultancy.

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